When Germany’s ultimatum – delivered, as the Kaiser had explained, ‘only with the friendliest intentions towards Belgium’ – expired in August 1914, von Emmich’s infantry crossed the frontier in parade-ground order, accompanied by horse-drawn field kitchens with fires burning and army cooks stirring the regimental stew.

They don’t wage war like that any more. Indeed the big wars are rarely now between neighbours: one state will cross a continent or an ocean to attack or invade, or occasionally to defend, another. The choreographed exchange of diplomatic threats, the ultimatum, the formal declaration of a state of war, have been pretty much dispensed with. The last time the United Kingdom declared war was against Romania in 1941.

Among the casualties of warfare during the last hundred years have been many of the rules governing the conduct of hostilities. The Hague and Geneva Conventions describe the members of warring states’ armies and militias as ‘lawful combatants’. The reason they contain no category of ‘unlawful combatant’ is that no such antithesis is recognised in international law. The counterpart of the lawful combatant, who enjoys special protections (in particular from the law of homicide), is the civilian, who is entitled to the ordinary protection of the law. In a militarily occupied country such protection is likely in practice to be attenuated or disregarded in favour of arbitrary and brutal forms of justice; but that does not make the torture of partisans or the execution of hostages lawful.

The unlawful combatant is a false extrapolation, a quasi-legal description applied to an opponent, or suspected opponent, who lacks the overt authority of a sovereign state. But such a person is in law a civilian, at risk of being held to account by the law of the state in whose hands he finds himself, but in no way deprived of the right to due process in order to determine, first, what his status actually is and, second, whether he is guilty of a crime known to the law. Captured guerrillas may have little ultimately to hope for, but they are entitled not to be summarily executed or tortured or held indefinitely without trial.

The Bush administration after 9/11 set out to change all that. With the designation of unlawful combatant it created a self-sustaining doctrine that there are individuals who, having attacked the US or opposed it by force, have forfeited all rights both as combatants and civilians: in short, a new class of outlaw.

The potential impact of this doctrine on the morality of state conduct can be gauged by the new edition of Nigel Rodley’s classic work on the treatment of prisoners, both lawful and de facto. Rodley, an academic lawyer and a member of the UN Human Rights Committee, accepts that international law has been ‘decidedly ambitious in the limits it sets on the behaviour of government authorities towards those in their hands’; but his answer is to back ambition with legal action. The international community over recent decades has achieved wide agreement on the abolition of the death penalty, the prevention and redress of enforced disappearances and extra-legal executions, the humane treatment of prisoners, the control of firearms in the hands of public officials, and – albeit with the signal abstention of the United States – the Rome Statute setting up the International Criminal Court. Enforcement remains the big problem, but the UK at least gave grounds for optimism when its highest court in 1999 ruled that General Pinochet could not claim sovereign immunity from extradition on charges of torture.

The reaction to the 9/11 atrocity set this clock running backwards. Rodley is clear that years of uneven but real progress towards a humane international legal order were halted and in significant part reversed. ‘General or customary international law was essentially brushed aside … on the view that customary international law “does not bind the executive branch under the constitution because it is not federal law”.’ But the courts, including the US Supreme Court, have in some measure halted or slowed this reversal, and Rodley is not wholly pessimistic about the future.

The full text of this book review is only available to subscribers of the London Review of Books.

Letters

It isn’t true, as Stephen Sedley asserts, that ‘slaving became assimilated in international law to piracy, a capital offence,’ after Britain and the US outlawed the slave trade for their nationals in 1807-8 and the Congress of Vienna issued a moral condemnation of the trade (LRB, 24 June). For more than four decades after Britain criminalised the slave trade, the judges who administered international law in British courts considered it a legal activity for foreigners. The key judgment was Sir William Scott’s in the case of Le Louis. Scott, the senior judge in the High Court of Admiralty, overruled the condemnation by the Freetown vice-admiralty court of a French slaving vessel in 1817, and upheld the ‘natural’ right of the French crew to resist an unlawful search. (Twelve men from the Queen Charlotte had been killed in seizing Le Louis.)

Scott’s opinion was a masterly summation of customary international law with respect to the freedom of the high seas. The law’s fundamental principles were, first, ‘the perfect equality and entire independence of all distinct [sovereign] states’ and, second, their ‘equal right to the uninterrupted use of the unappropriated parts of the ocean for their navigation’. On the high seas ‘no one state, or any of its subjects, [had] a right to assume or exercise authority over the subjects of another.’ The right of visit and search, which belligerents legitimately exercised in wartime in the interests of self-defence, could not lawfully be exercised in peacetime, without a prior treaty establishing that right. Since the search of Le Louis had been unlawful, any evidence of slaving so revealed could not be part of the legal case for condemning the vessel.

Scott demolished the Crown’s contention that the declarations of the European powers at the Congress of Vienna condemning the slave trade as repugnant to the principles of humanity and universal morality sufficed to make it a crime on a par with piracy, which all states had a right and duty to suppress. Slavery was a legal institution in British dominions and buying and transporting African slaves had once been a legal business actively encouraged by British governments. Slaving, Scott argued, ‘cannot be deemed a legal piracy’:

It wants some of the distinguishing features of that offence. It is not the act of freebooters, enemies of the human race, renouncing every country, and ravaging every country in its coasts and vessels indiscriminately; but of persons confining their transactions (reprehensible as they may be) to particular countries. It is not the act of persons … assaulting coasts … against the will of [African] governments and the course of their laws, but of persons [carrying] on a traffic not only recognised but invited by the institutions and the administrations of those barbarous communities.

Scott warned the British executive that British courts administering international law were bound to respect the legality of slave-trading by nationals of states which had not positively outlawed the activity: if their slave cargoes were seized by the Crown’s officers, then they had to be restored to them; ‘and if not taken under innocent mistake, to be restored with costs and damages’. Although he did not award costs and damages to the plaintiff in what was a ‘test’ case, Scott’s judgment opened the way for foreign slave-traders to sue British naval officers for financial restitution if they broke international law in suppressing the slave trade, and they had considerable success.

Bernard Waites’s account of the judicial sabotage of the international ban on slave-trading following the Napoleonic Wars is perfectly correct, but it does not falsify what I wrote (Letters, 8 July). It was indeed the case that slaving became assimilated to piracy; but, like the common law prohibition of slave-holding in the previous century, this took decades to achieve in the face of sometimes dogged judicial opposition. In both instances, the first expedient was to decide that the ban might apply in Britain or to British vessels, but that it could not affect what was done in the colonies or by foreign ships. That was the story of English law following Mansfield’s historic decision in James Somersett’s case in 1772 (a decision Mansfield himself later went back on), and it was the story Waites tells about the Admiralty Court’s retrograde decision in the case of Le Louis, which was still having effects as late as 1860. But the fact that some judges are resistant or obstructive to new developments does not mean that the law has not changed. It means that change in the law is a process which can take time – unless Parliament intervenes, which the UK Parliament for decades failed to do.